1. Field of the Invention
This invention relates to a video disk playback apparatus for reproducing video image signals recorded on a disk, such as a laser disk.
2. Description of the Prior Art
Recently, as the use of audio-video (AV) related appliances has diversified, the laser disk (LD) or other video disk playback apparatuses are not limited to mere reproduction of video images recorded in the disk, but are modified in various versions for displaying a still picture using a memory, displaying the track number, time, or other information by overlapping on a screen, and others. As further developments, there is a mounting demand for a multifunctional apparatus, such as display of characters, still picture or graphics in addition to the original picture when reproducing from the LD. Referring to two prior patents, the conventional video disk playback apparatus is described below.
The Japanese Patent Publication No. 62-263789 discloses a video disk playback apparatus with a video memory. By applying this technique, the picture during playback can be displayed as a still picture. The Japanese Patent Publication No. 61-77168 discloses, in its FIG. 5, a technique of displaying the track number or time information or the like recorded in the blanking period of the video signal or in the subcode of the CD on the screen by converging into a video signal using a character generator.
Such a constitution, however, requires a digital data memory for displaying the digital data read out from the disk by overlapping on the moving picture read out from the disk or its still picture. (In FIG. 5 of the No. 61-77168 patent, digital data memory is not mentioned, but it is evident that a memory for the portion of the characters to be displayed is required in the block of the character generator.) In particular, if the digital data is large in capacity such as for a graphic picture, it leads to a higher cost.